Fix SSL issues when reading remote ZIP files

This is caused by our self-signed PureStorage certs. Once that's taken care of this commit can be reverted.

app/models/zip_file.rb

@@ -65,7 +65,7 @@ class ZipFile
 
       def read_from_s3(blob)
         url = blob.url(expires_in: 6.hour)
-        remote_io = ZipKit::RemoteIO.new(url)
+        remote_io = RemoteIO.new(url)
         reader = Reader.new(remote_io)
         yield reader
       end

app/models/zip_file/remote_io.rb

@@ -0,0 +1,44 @@
+class ZipFile::RemoteIO < ZipKit::RemoteIO
+  protected
+    def request_range(range)
+      with_http do |http|
+        request = Net::HTTP::Get.new(@uri)
+        request.range = range
+        response = http.request(request)
+
+        case response.code
+        when "206", "200"
+          response.body
+        else
+          raise "Remote at #{@uri} replied with code #{response.code}"
+        end
+      end
+    end
+
+    def request_object_size
+      with_http do |http|
+        request = Net::HTTP::Get.new(@uri)
+        request.range = 0..0
+        response = http.request(request)
+
+        case response.code
+        when "206"
+          content_range_header_value = response["Content-Range"]
+          content_range_header_value.split("/").last.to_i
+        when "200"
+          response["Content-Length"].to_i
+        else
+          raise "Remote at #{@uri} replied with code #{response.code}"
+        end
+      end
+    end
+
+  private
+    def with_http
+      http = Net::HTTP.new(@uri.hostname, @uri.port)
+      http.use_ssl = @uri.scheme == "https"
+      # FIXME: Disable SSL verification for now to avoid issues with our self-signed certificates for PureStorage
+      http.verify_mode = OpenSSL::SSL::VERIFY_NONE
+      http.start { yield http }
+    end
+end